The conservation of beneficial arthropods in agricultural landscapes: a challenge for the success of sustainable agriculture

Abstract

In the past, agricultural landscapes were a mosaic of crops, hedgerows, field margins, woodlands, wetlands and fallow fields. It is unfortunate that the current trend toward agriculture intensification is based on the replacement of diverse landscapes by contiguous large-scale monocultures. One of the consequences of this trend is the reduction of the total area of suitable habitats for wildlife, including arthropods that act as natural enemies of crop pests. This process has important implications to the use of biological control as a means to making agriculture sustainable. Extensive monocultures fail to provide key resources for natural enemies, such as nectar, pollen, over-wintering sites, refuges and alternative prey, offering almost no conditions for the survival and persistence of natural enemies in the long term. This problem can become a serious limitation to the application of biological control strategies based on the conservation of natural enemies of insect pests. Therefore, it is necessary to develop farming approaches for sustainable agriculture that seek to incorporate more biodiversity in agricultural landscapes in order to restore the vital resources required for the conservation of beneficial arthropods. Some authors have suggested that managing the structure of agricultural landscapes can facilitate a more ecologically based approach to integrated pest management. This paper discusses supporting evidence from a temperate agriculture perspective, the factors constraining the adoption of this approach by farmers, and the actions needed to overcome these constraints.